Behind the scarp revetments there are three long galleries incorporating casemated rooms for both musketry and carronades, all for the defence of the ditch. These are constructed mainly in brick laid to English bond, usually with axial semi-circular vaults of stretchers, invariably whitewashed. The west Musketry gallery consists of four musketry casemates to the south and nine casemates to the north, connected to the terreplein by a flight of stairs. (location accurate to the nearest 1m based on available information)